Telephone-receiver.



Patnted Dec. 3, mm.

H. LIEBREICH.

TELEPHONE RECEIVER.

(Application filed Nov. 30, 1900.,

(.No Model.)

awe/Mica fi ams Zz'efirez'ck abtmmm m: cams PETERS 00 PHOTO-UTHQ, wnsumcmu, n. c

-UNITED STATES PATENT ()FFIGE.

HANS LIEBREICH, OF DETROIT, MICHIGAN.

TELEPHONE-RECEIVER.

:3 PEGIFICATIQN forming part of Letters Patent No. 687,998, dated December 3, 1901.

Application filed November 30, 1900. Serial No. 38,197- (No model.)

To all whom, it may concern:

Be it known that I, HANS LIEBREICH, a citizen of the United States, residing at Detroit, in the county of WVayne and State of Michigan, have invented certain new and useful Improvements in Telephone-Receivers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in telephone-receivers; and it consists in a receiver employing diaphragms properly held in position, a horseshoe-magnet mounted in proper relation with respect to the diaphragms, coils connected with the poles of said magnet and electrically connected with the line-wires of the telephone, and means for increasing the strength of the magnet, whereby very powerful results will be produced in the action of the diaphragms.

It also consists in a receiver having a pair of diaphragms, a magnetinterposed between them, pole-pieces carried by the magnet, coils arranged about the said pole-pieces and connected with a telephone-line, the said polepieces being arranged to cause the vibration of the diaphragms, and means for connecting the centers of the diaphragms, whereby they will be vibrated in unison and an accumulated effect will be the result.

It further consists in certain other novel constructions, combinations, and arrangements of parts, as will be hereinafter more fully described and specifically claimed.

In the accompanying drawings, Figure 1 is a perspective View of a receiver embodying the features of this invention. Fig. 2 is a central longitudinal section through the same. Fig. 3 is a cross-section through the receiver casing, the magnet and its poles being shown in elevation. Fig. 4 is an edge View of the magnet removed from the receiver.

My improved receiver is so constructed as to be exceedingly compact in form and yet so as to be far more efficient in the reproduction of sound than receivers or microphones in common use. I preferably make the said receiver in a double form, employing two diaphragms 1 1, mounted withina casing 2. The receiver can of course be made with a single diaphragm without departing from the spirit of the invention, and I do not wish to be understood as limiting myself to the use of two diaphragms. The double form I find to be the most effective one, and for that reason'I will describe myinvention in connection with drawings illustrating only the receiver as provided with two diaphragms. The casing 2 is formed of a central ring portion 3, to the outer ends of which are secured the diaphragms 1 1. These diaphragms rest against rings 4 4, which are screwed into the ends of the ring 3. By adjusting these rings 4 4 the distance between the diaphragms can be regulated to a nicety, as well as the distance of the said diaphragms from the poles of the magnet within the receiver. Retaining-rings 5 5 are screwed upon the outer surface of the ring 3 and clamp the diaphragms at their edges to the rings 4 4. Cap-pieces 6 6 maybe applied to the rings 5 5 outside the diaphragms, the said cap-pieces being centrally perforated to permit sound to escape from the receiver. The peripheries of the ring 3, the rings 5 5, and the caps 6 6 are preferably serrated, so that all the parts can be easily turned by hand upon their screwthreads,so as to adjust their relative positions.

\Vithin the ring 3 is secured a suitable magnet 8, which is preferably of a horseshoe form, having its pole ends bent inwardly, as at 9 9, toward the center of the casing, while the remainder of the magnet is disposed around the inner surface of the ring 3. The magnet 8 is preferably a permanent'one and is inleaves or plates 10 10 upon each side thereof. These plates are built up upon the opposite surfaces of the magnet 8, and their free ends extend toward the poles 9 9. The

increase the speed with which the pole-pieces 12 12 may be magnetized or demagnetized, I

creased in its power by applying a series of inner plates are preferably made longer than preferably form k'erfs or slots 13 13 in the ends of the said pole-pieces, the said kerfs extending inwardly to points near the pole ends of the magnet. Around the oppositelyextending ends of the pole-pieces are wound coils 14 14, a coil being preferably secured upon each side of the poles 9 9. The coils on each pole-piece are electrically connected with each other, and one set of coils on one of the poles 9 is connected with the other set on the other pole 9, and both sets of coils are connected, by means of wires 15 15, with binding-posts 16 16 on the outer surface of the easing. These binding-posts receive the ends of the line-wires 17, so that a current of electricity may be passed from the telephone-line through all the coils on the pole-pieces 12 12.

The magnet 8 is preferably removably secured in the casing, and a simple manner of securing the magnet in the said casing is illustrated in the drawings, in which it will be seen that the periphery of the said magnet, together with the plates secured thereto, is formed with screw-threads l8, adapted to engage the screw-threads 19 upon the inner surface of the ring 3. This construction also makes it possible to adjust the position of the magnet between the diaphragms 1 1.

In order to accumulate the vibrations of the two diaphragms, which are polarized and move in unison, and thus double their power, I connect the diaphragms, preferably at their centers, by a rod or bar 20, which may be made of any suitable material and may be riveted at its ends or otherwise secured to the said diaphragm. It thus transpires that when one diaphragm is vibrated in one direction the other one will be simultaneously vibrated in the same direction. \Vhen impulses are passed over the line-wire, they will pass through the coils 14 14 and magnetize the pole-pieces 12 12 correspondingly, the said pole-pieces attracting the diaphragms 1 1. Since the pole-pieces are arranged opposite difierent points in the diaphragms, the diaphragms will be actuated in wave forms and will be found to communicate sound in a very loud and distinct manner.

By making a receiver as above described I am enabled to form one which is quite small and yet which is very sensitive even to the slightest sound and impulses and reproduces the same with considerably augmented power.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

1. A telephone-receiver, comprising a casing, diaphragms mounted therein, a magnet mounted in the receiver, and having poles opposite both the diaphragms at different points, whereby the vibrations of the diaphragms will produce sounds with great clearness and strength, and means for adjusting the posi tion of the magnet between the diaphragms byrotating the said magnet in the casing, su bstantially as described.

2. A telephone-receiver comprising a casing, diaphragms secured therein, a horseshoemagnet interposed between thediaphragms and having screw-threads on its periphery engaging corresponding threads inside the casing so that by turning the magnet, its position between the diaphragms may be varied, and means for varying the magnetic force of the magnets poles, substantially as described.

3. A receiver for telephones comprising a.

casing, diaphragms mounted therein, a magnet adj ustably mounted between the diaphragms so that it may be moved nearer to one or the other as may be desired, pole-pieces carried by the said magnet and extending to ward both the diaphragms and arranged to afiect them at different points, and means for increasing or diminishing the magnetic force of the said poles, the casing having openings over both diaphragms, whereby the sounds produced by the same may be heard at either end of the instrument, substantially as described.

4. A telephone-receiver, comprising a casing, a pair of diaphragms mounted therein, a rod or connecting-piece interposed between the diaphragms for causing them to operate in unison, and a magnet interposed between the diaphragms but not connected therewith and adapted to act directly on both of them for vibrating the same in accordance with impulses received from the telephone-lines, substantially as described.

5. A telephone-receiver comprising a casing made up of a series of rings, some of the said rings being adapted to hold diaphragms in position, diaphragms supported by said rings, one of the said rings being provided with internal threads, a magnet having threads upon its periphery adapted to engage said internal threads, and means for energizing the magnet, the structure being such that the diaphragms may be adjusted with respect to each other and the position of the magnet may be adjusted between the same, substantially as described.

6. A telephone-receiver comprising a cas ing, a pair of diaphragms mounted therein, means connecting the said diaphragms so that they will vibrate simultaneously, a magnet interposed between the diaphragms and having pole-pieces extending to points adjacent to the surface of the diaphragms,the said pole-pieces being kerfed or slotted at their ends, a series of coils surrounding the pole-pieces on each side of the magnet, Wires connecting all the coils together and with the line-wire, whereby impulses received from the line may vary the magnetic power of the pole-pieces and produce a wavy vibration of the diaphragms, substantially as described.

In testimony whereof I hereunto affix my signature in presence of two witnesses.

HANS LlEBREIOI-I. 

